The research proposed here will investigate the abilities of elderly subjects and patients with Dementia of the Alzheimer's Type (DAT) to understand sentences and to use the meaning of sentences to accomplish tasks. It will study different aspects of sentence comprehension tasks, providing new information about the abilities of elderly subjects and patients with DAT to process syntactic form and sentence meaning. It will examine the relationship between impairments in verbal working memory and those of sentence comprehension in these populations. It will also provide new information about changes in the neural basis for the process of sentence comprehension in elderly subjects and patients with DAT. The results of these studies will increase our understanding of the nature of the sentence comprehension process in aging and DAT, and the nature of the neural basis for this process in these populations.